Dermoid

Dermoid cyst Epidermoid cyst features plus adnexa of skin cyst contains sebum, squames, and hair Keratin (-r) Midline cerebellum fourth ventricle skull spinal dura cauda equina... 

Dermoid cysts are frequently midline cysts, possibly arising from embryonic inclusions of skin at the time of closure of the neural groove (see Table 20.13). They occur between the cerebellar hemispheres, in the fourth ventricle, in the lumbosacral region of the cord, and in the skull. These cysts may involve CNS, meninges, or both. Ruptured dermoid cysts can cause sterile meningitis and inflammation resembling an abscess. Identification of squamous epithelial cells with CK or cholesterol clefts within the inflammation are clues to its true cause. 

Dermoid cysts or mature cystic teratomas are composed of mature tissue from at least two of the three... 

In the vast majority (88%), dermoid cysts are uni-lociflar cystic lesions filled with sebaceous material. A protuberance, the Rokitansky nodule, or dermoid plug, projects into the cavity and is the hallmark of dermoids (Fig. 9.17). It contains a variety of tissues, often including fat and calcifications, which represent teeth or abortive bone. Fat is detected in over 90%,... 

A minority of dermoid cysts will demonstrate no fat or only small foci of fat within the wall or the Rokitansky nodule (Fig. 9.28) [73]. Yamashita et al. reported that 15% of mature teratomas did not show fat within the cystic cavity. Approximately half of these cases displayed small amounts of fat within the wall of the dermoid or the dermoid plug. In 8% of henign teratomas, no fat could be detected [73]. 

Dermoids are usually asymptomatic and tend to grow slowly. This is why some gynecologists advo-... 

Sonographic assessment of dermoid cysts is often limited by its variety of appearance. 

Fig. 9.29). Another typical feature on CT is the presence of calcifications within the cyst wall or the dermoid plug. 

Fig. 9.29. Dermoid torsion in CT. Noncontrast transaxial CT in a 37-year-old female who presented with acute pelvic pain. A well-demarcated left adnexal lesion with fatty attenuation values ( s-terisk) is located adjacent to the uterus. Linear calcifications are found at its medial wall. An area of higher density within the fatty tissue correlated with floating hair in the macroscopic specimen. The homogenous wall thickening (arrow) is caused by edema due to torsion of the dermoid...

In a patient with acute abdomen and a dermoid, the presence of sebaceous fluid floating in the peritoneal cavity can suggest rupture [75],... 

When no or only small amounts of fat are present (8%), dermoids are not distinguishable from benign cystic ovarian tumors or ovarian cancer (Fig. 9.28) [75]. 

Fig. 9.31. Collision tumor of the ovary. CT at the level of the mid pelvis in a 65-year-old woman with sonographically suspected ovarian cancer. A cystic right adnexal mass is demonstrated showing multiple thin septa-tions and a 3-cm lesion with fat density and mural calcifications (asterisk). Pathologically, a collision tumor composed of a benign mucinous cystadenoma and a benign dermoid was diagnosed...

Quinn SF, Erickson S, Black WC (1985) Cystic ovarian teratomas the sonographic appearance of the dermoid plug. Radiology 155 477-478... 

Ekici E, Soysal M, Kara S, Dogan M, Gokmen O (1996) The efficiency of ultrasonography in the diagnosis of dermoid c) s. Zentralbl Gynakol 118 136-141... 

Caspi B,AppelmanZ,RabinersonDet al (1997) The growth pattern of ovarian dermoid cysts a prospective study in premenopausal and postmenopausal women. Fertil Steril... 

Bazot M, Cortez A, Sananes S, Boudghene F et al (1999) Imaging of dermoid cysts with foci of immature tissue. J Comput Assist Tomogr 23 703-706... 

The finding of a cystic ovarian tiunor, especially a dermoid cyst in young women who present with acute pain and vomiting is highly suspicious of adnexal torsion. 

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